JP6773917B2 - Wafer support - Google Patents

Description

The present invention relates to a wafer support.

As a wafer support base, an RF electrode and a heater electrode are embedded in a disk-shaped ceramic substrate having a wafer mounting surface in this order from the wafer mounting surface side. For example, Patent Document 1 includes a wafer support of this type including a circular RF electrode and an annular RF electrode embedded in a ceramic substrate so that the depths from the wafer mounting surface are different from each other. It is disclosed. A flat plate upper electrode is arranged at a position of the wafer support base facing the wafer mounting surface. Then, high-frequency power is applied between the parallel plate electrode composed of the flat plate upper electrode and both RF electrodes of the wafer support to generate plasma. Patent Document 1, when generating the plasma, is described and can be well controlled density distribution of the plasma by applying a different high frequency power to the circular R F electrode and the annular RF electrodes.

Japanese Patent No. 5896595

However, when generating plasma, the distance between the flat plate upper electrode and the circular RF electrode and the distance between the flat plate upper electrode and the annular RF electrode are different, and the dielectric material between the wafer mounting surface and the circular RF electrode is different. The thickness of the layer (ceramic substrate) and the thickness of the dielectric layer between the wafer mounting surface and the annular RF electrode are also different. Therefore, the density of plasma may become non-uniform.

The present invention has been made to solve such a problem, and an object of the present invention is to suppress the occurrence of defects due to non-uniform plasma density.

In order to achieve at least one of the above-mentioned objects, the wafer support of the present invention adopts the following configuration.

That is, the wafer support of the present invention is
A wafer support base in which RF electrodes and heater electrodes are embedded inside a disk-shaped ceramic substrate having a wafer mounting surface.
The RF electrode is composed of a plurality of RF zone electrodes provided for each zone in which the wafer mounting surface is divided into a plurality of zones.
The plurality of RF zone electrodes are provided in at least two stages having different distances from the wafer mounting surface.
The heater electrode is composed of a plurality of heater zone electrodes provided for each zone in which the wafer mounting surface is divided into a plurality of zones in the same manner as or different from the RF zone electrode, and the plurality of RF zone electrodes are formed. It is independently connected to a plurality of RF zone electrode conductors through electrode terminals provided on the back surface of the ceramic substrate.
The plurality of heater zone electrodes are independently connected to a plurality of conductors for heater zone electrodes through electrode terminals provided on the back surface of the ceramic substrate.
It is a thing.

In this wafer support, the plurality of RF zone electrodes and the plurality of heater zone electrodes are the conductors for the plurality of RF zone electrodes and the plurality of RF zone electrode conductors through the electrode terminals provided on the surface (back surface) opposite to the wafer mounting surface of the ceramic substrate. It is independently connected to a plurality of conductors for heater electrodes. Therefore, different high-frequency power can be supplied to each RF zone electrode, and the density of plasma on the wafer mounted on the wafer mounting surface can be made uniform to some extent. On the other hand, since the plurality of RF zone electrodes are provided in at least two stages, the plasma density may become non-uniform. However, even in such a case, since different electric power can be supplied for each heater zone electrode, the variation in film formation property for each zone can be compensated and adjusted by adjusting the heater temperature. Therefore, it is possible to suppress the occurrence of defects due to the non-uniform plasma density.

In the wafer support of the present invention, the RF electrode includes, as the plurality of RF zone electrodes, a circular electrode concentric with the ceramic substrate or an electrode obtained by dividing the circular electrode into a plurality of portions, and further, the circular electrode or the circular electrode. The outside of the electrode obtained by dividing the electrode into a plurality of parts may include one or more annular electrodes concentric with the ceramic substrate or an electrode obtained by dividing at least one of the annular electrodes into a plurality of parts. Since the plasma density distribution is often different between the inner peripheral portion and the outer peripheral portion of the ceramic substrate, the circular electrode (or the electrode obtained by dividing the circular electrode into a plurality of electrodes) and one or more annular electrodes (or the annular electrodes) are described. It is preferable to divide the electrode into a plurality of electrodes). For example, as the RF zone electrode, a circular electrode concentric with the ceramic substrate and one or more annular electrodes concentric with the ceramic substrate may be provided outside the circular electrode. Alternatively, a pair of semicircular electrodes in which the circular electrodes concentric with the ceramic substrate are divided in half, and one or more annular electrodes concentric with the ceramic substrate may be provided outside the semicircular electrodes. Alternatively, the annular electrode may be divided into a plurality of parts.

In the wafer support of the present invention, at least one heater zone electrode may be arranged in the gap between the RF zone electrodes when the ceramic substrate is viewed from the wafer mounting surface. When the applied RF power is increased, it is advantageous to increase the gap interval because RF interference can be suppressed. However, the plasma density decreases in the gap portion where the RF electrode does not exist, and the in-plane plasma density becomes non-uniform. There is. Therefore, by arranging the heater zone electrode in the gap region, it is possible to compensate and adjust the variation in film formation caused by the non-uniformity of the plasma density by adjusting the temperature distribution, that is, the heater temperature, which is effective. In this case, the heater zone electrode arranged in the gap may be a gap heater zone electrode having a shape corresponding to the gap. In this way, it becomes easy to individually control the temperature of the gap by the gap heater zone electrode, and the variation in film formation in the vicinity of the gap can be compensated and adjusted by adjusting the temperature of the gap heater zone electrode.

Alternatively, in the wafer support of the present invention, the ceramic substrate is arranged so that the shapes of the plurality of RF zone electrodes and the shapes of the plurality of heater zone electrodes match when viewed from the wafer mounting surface. You may. In this way, the temperature of each RF zone electrode can be individually controlled by the corresponding heater zone electrode. Here, the "shape of the heater zone electrode" means, for example, the shape of a region in which the coil is routed when the heater zone electrode is composed of a coil.

In the wafer support of the present invention, the plurality of RF zone electrodes include a circular electrode concentric with the ceramic substrate and one or more annular electrodes concentric with the ceramic substrate on the outside of the circular electrode, and the heater. The plurality of heater zone electrodes constituting the electrodes are provided on the same plane, and the height of the plurality of RF zone electrodes from the heater electrodes is higher (or lower) as the RF zone electrodes are closer to the center of the ceramic substrate. ) May be. In that case, the thickness of the ceramic substrate on each RF zone electrode (that is, the thickness of the dielectric layer) may be the same.

The wafer support of the present invention includes a hollow ceramic shaft joined to the central region of the surface of the ceramic substrate opposite to the wafer mounting surface, and is used for the plurality of RF zone electrode conductors and the heater electrode. The conductor may be arranged inside the ceramic shaft.

In the wafer support base of the present invention, the plurality of RF zone electrodes may be provided in multiple stages so that the distances from the wafer mounting surface are different, or two or more of the plurality of RF zone electrodes are provided in the same stage although they are in multiple stages. RF zone electrodes may be provided. Further, the plurality of heater zone electrodes may be provided on the same plane, or may be provided so as to have different distances from the wafer mounting surface. The shape and number of RF zone electrodes and the shape and number of heater zone electrodes can be arbitrarily determined.

The perspective view which shows the schematic structure of the plasma generator 10. A cross-sectional view taken along the line AA of FIG. BB sectional view of FIG. The perspective view which shows the arrangement of the RF electrode 23 and the heater electrode 30. The perspective view which shows the arrangement of the RF electrode 23 and the heater electrode 30 of another example. The perspective view which shows the arrangement of the RF electrode 23 and the heater electrode 30 of another example. The perspective view which shows the arrangement of the RF electrode 23 and the heater electrode 30 of another example. The plan view which shows another example of the RF electrode 23. The plan view which shows another example of the RF electrode 23. FIG. 3 is a cross-sectional view of a wafer support base provided with a ceramic substrate 422. FIG. 6 is a cross-sectional view of a wafer support base provided with a ceramic substrate 522. FIG. 6 is a cross-sectional view of a wafer support base provided with a ceramic substrate 622.

A preferred embodiment of the present invention will be described below with reference to the drawings. 1 is a perspective view of the plasma generator 10, FIG. 2 is a sectional view taken along the line AA of FIG. 1, FIG. 3 is a sectional view taken along the line BB of FIG. 1, and FIG. 4 is a perspective view showing the arrangement of the RF electrode 23 and the heater electrode 30. It is a figure.

As shown in FIG. 1, the plasma generator 10 includes a wafer support base 20 and an upper electrode 50.

The wafer support base 20 is used to support and heat the wafer W that performs CVD, etching, or the like using plasma, and is mounted inside a chamber for a semiconductor process (not shown). The wafer support 20 includes a ceramic substrate 22 and a hollow ceramic shaft 29.

As shown in FIG. 2, the ceramic substrate 22 is a disk-shaped member made of ceramic (for example, made of alumina or aluminum nitride). The surface of the ceramic substrate 22 is a wafer mounting surface 22a on which the wafer W can be mounted. A ceramic shaft 29 is joined to the center of the surface (back surface) 22b of the ceramic substrate 22 opposite to the wafer mounting surface 22a. As shown in FIGS. 2 to 4, the RF electrode 23 and the heater electrode 30 are embedded in the ceramic substrate 22. The RF electrode 23 and the heater electrode 30 are embedded in this order from the side closest to the wafer mounting surface 22a.

The RF electrode 23 is provided parallel to the wafer mounting surface 22a (including the case where it is substantially parallel, the same applies hereinafter). The RF electrode 23 is a first RF zone electrode 24 provided in a zone inside a circle 21 (see FIG. 3) having a predetermined radius (for example, more than half the radius of the ceramic substrate 22) from the center of the ceramic substrate 22, and the circle 21 thereof. It is composed of a second RF zone electrode 25 provided in the outer zone of the above. That is, the first and second RF zone electrodes 24 and 25 are provided for each zone in which the wafer mounting surface 22a is divided into a plurality of zones. The first RF zone electrode 24 is a circular electrode concentric with the ceramic substrate 22. The second RF zone electrode 25 is an annular electrode concentric with the ceramic substrate 22, and is separated from the first RF zone electrode 24. The first and second RF zone electrodes 24 and 25 are embedded inside the ceramic substrate 22 so as to have different heights (distance from the wafer mounting surface 22a). Here, the first RF zone electrode 24 is provided so as to be close to the wafer mounting surface 22a. The first RF zone electrode 24 is provided so as to overlap the circular central region 22c (two-dot chain line in FIGS. 2 and 3) on which the ceramic shaft 29 is projected onto the ceramic substrate 22, but the second RF zone electrode 25 is provided. , Is provided at a position outside the central region 22c. The first and second RF zone electrodes 24 and 25 are both made of a conductive mesh sheet.

As shown in FIG. 2, the first RF zone electrode 24 has an electrode terminal 24a connected to substantially the center of the back surface. The electrode terminal 24a is provided so as to be exposed to the outside from the back surface 22b of the ceramic substrate 22. The first RF zone electrode 24 is connected to the conductor 34 for the first RF zone electrode via the electrode terminal 24a. The conductor 34 for the first RF zone electrode is connected to the first AC power supply 44 via the hollow inside of the ceramic shaft 29 and the lower opening.

As shown in FIGS. 2 and 4, the second RF zone electrode 25 has a connecting conductor 27 made of a conductive mesh sheet. The connecting conductor 27 is provided radially from the center of the annular second RF zone electrode 25 and is arranged so as not to interfere with the electrode terminal 24a. The connecting conductor 27 is provided so that the electrode terminal 25a is exposed to the outside from the back surface 22b of the ceramic substrate 22. The electrode terminals 25a are also arranged so as not to interfere with the electrode terminals 24a. The second RF zone electrode 25 is connected to the second RF zone electrode conductor 35 via the connecting conductor 27 and the electrode terminal 25a. The conductor 35 for the second RF zone electrode is connected to the second AC power supply 45 via the hollow inside of the ceramic shaft 29 and the lower opening.

The heater electrode 30 is provided parallel to the wafer mounting surface 22a. The heater electrode 30 is composed of a first heater zone electrode 31 provided in the inner zone of the circle 21 (see FIG. 3) and a second heater zone electrode 32 provided in the outer zone of the circle 21. It is configured. That is, the first and second heater zone electrodes 31 and 32 are provided for each zone in which the wafer mounting surface 22a is divided into two like the first and second RF zone electrodes 24 and 25. The first heater zone electrode 31 and the second heater zone electrode 32 are embedded in the ceramic substrate 22 so as to have the same height (that is, on the same plane).

The first heater zone electrode 31 has two electrode terminals 31a and 31b, and a coil is formed from one electrode terminal 31a to the other electrode terminal 31b in a one-stroke manner over the entire circular region inside the circle 21. It is wired. The electrode terminals 31a and 31b are connected to the first heater power supply 47 via the conductors 36 and 36 for the first heater zone electrodes. Note that FIG. 2 shows only one electrode terminal 31a for convenience. The first heater zone electrode 31 is provided so as to overlap the first RF zone electrode 24 when viewed in a plan view.

The second heater zone electrode 32 has two electrode terminals 32a and 32b, and is coiled from one electrode terminal 32a to the other electrode terminal 32b in a one-stroke manner over the entire outer annular region of the circle 21. Is wired. The electrode terminals 32a and 32b are connected to the second heater power supply 48 via the conductors 37 and 37 for the second heater zone electrodes. Note that FIG. 2 shows only one electrode terminal 32a for convenience. The second heater zone electrode 32 is provided so as to overlap the second RF zone electrode 25 when viewed in a plan view.

The materials of the RF electrode 23, the connecting conductor 27, and the heater electrode 30 may be the same or different. The material is not particularly limited as long as it has conductivity, and examples thereof include Mo, W, Nb, Mo compound, W compound, and Nb compound. Of these, those having a small difference in thermal expansion coefficient from the ceramic substrate 22 are preferable.

The ceramic shaft 29 is a cylindrical member made of the same ceramic as the ceramic substrate 22. The upper end surface of the ceramic shaft 29 is bonded to the back surface 22b of the ceramic substrate 22 by diffusion bonding or TCB (Thermal compression bonding). The TCB is a known method in which a metal bonding material is sandwiched between two members to be bonded and the two members are pressure-bonded while being heated to a temperature equal to or lower than the solid phase temperature of the metal bonding material.

As shown in FIG. 1, the upper electrode 50 is fixed at an upper position (for example, the ceiling surface of a chamber (not shown)) of the ceramic substrate 22 facing the wafer mounting surface 22a. The upper electrode 50 is connected to the ground.

Next, a usage example of the plasma generator 10 will be described. The plasma generator 10 is arranged in a chamber (not shown), and the wafer W is placed on the wafer mounting surface 22a. Then, high-frequency power is supplied to the first RF zone electrode 24 from the first AC power supply 44, and high-frequency power is supplied to the second RF zone electrode 25 from the second AC power supply 45. By doing so, plasma is generated between the parallel plate electrode composed of the upper electrode 50 and the RF electrode 23 embedded in the ceramic substrate 22, and the plasma is used to perform CVD film formation or etching on the wafer W. Or something. Further, the temperature of the wafer W is obtained based on a thermocouple detection signal (not shown), and the voltage applied to the first heater zone electrode 31 is applied to the first heater so that the temperature becomes a set temperature (for example, 350 ° C. or 300 ° C.). It is controlled by the power supply 47, and the voltage applied to the second heater zone electrode 32 is controlled by the second heater power supply 48.

In the wafer support 20 described in detail above, the first and second RF zone electrodes 24 and 25 have different high frequency powers (for example, different wattage powers at the same frequency, the same wattage powers at different frequencies, or different frequencies. (Electric power of different wattages, etc.) can be supplied, and the density of plasma on the wafer W mounted on the wafer mounting surface 22a can be made uniform to some extent. On the other hand, since the first and second RF zone electrodes 24 and 25 are provided in multiple stages, the plasma density may become non-uniform. However, even in such a case, since different electric power can be supplied to the first and second heater zone electrodes 31 and 32, the variation in film formation property in each zone can be compensated and adjusted by adjusting the heater temperature. .. Therefore, it is possible to suppress the occurrence of defects due to the non-uniform plasma density.

Further, since the plasma density distribution is often different between the inner peripheral portion and the outer peripheral portion of the ceramic substrate 22, the RF electrode 23 is placed on the inner peripheral side circular electrode (first RF zone electrode 24) and the outer peripheral side as described above. It is preferable to divide it into an annular electrode (second RF zone electrode 25).

Further, when the ceramic substrate 22 is viewed from the wafer mounting surface 22a (that is, when viewed in a plan view), the first and second RF zone electrodes 24 and 25 and the first and second heater zone electrodes 31 and 32 are aligned with each other. It is located in. Therefore, the temperature of each of the RF zone electrodes 24 and 25 can be individually controlled by the corresponding heater zone electrodes 31 and 32.

It is needless to say that the present invention is not limited to the above-described embodiment, and can be implemented in various aspects as long as it belongs to the technical scope of the present invention.

For example, in the above-described embodiment, the shapes of the first and second RF zone electrodes 24 and 25 and the shapes of the first and second heater zone electrodes 31 and 32 are arranged so as to match each other when viewed in a plan view. It may be arranged so as to have a similar shape. Further, as shown in FIG. 5, one of the first and second heater zone electrodes 131 and 132 (here) is provided in the donut-shaped gap G that appears between the first and second RF zone electrodes 24 and 25 when viewed in a plan view. Then, the second heater zone electrode 132) may be arranged so as to overlap each other. In FIG. 5, the same components as those in the above-described embodiment are designated by the same reference numerals. In FIG. 5, for convenience, the connecting conductors and RF zone electrode conductors and power supplies of the RF zone electrodes 24 and 25 are omitted, and the heater zone electrode conductors and power supplies of the heater zone electrodes 131 and 132 are also omitted. Further, the heater zone electrodes 131 and 132 omit the wiring pattern and show only the region where the coil is wired. When the applied RF power is increased, it is advantageous to increase the gap G interval to suppress RF interference, but the plasma density decreases in the gap G portion where the RF electrode does not exist, and the in-plane plasma density becomes inconvenient. May be uniform. Therefore, by arranging the second heater zone electrodes 132 so as to overlap in the region of the gap G, the variation in film forming property caused by the non-uniformity of the plasma density is compensated and adjusted by adjusting the temperature distribution, that is, the heater temperature. Can be done. Further, as shown in FIG. 6, the donut-shaped gap G that appears between the first and second RF zone electrodes 24 and 25 when viewed in a plan view has a shape corresponding to the gap G (here, the same as the gap G). The gap heater zone electrode 183 of the shape) may be provided. In this case, the shapes of the first and second heater zone electrodes 181, 182 are substantially the same as the shapes of the first and second RF zone electrodes 24 and 25, respectively. As a result, for example, even when the gap G between the first and second RF zone electrodes 24 and 25 is increased, it becomes easy to individually control the temperature of the gap G by the gap heater zone electrode 183. That is, the variation in film formation in the vicinity of the gap can be compensated and adjusted by adjusting the temperature of the gap heater zone electrode 183.

In the above-described embodiment, the heater zone electrodes 31 and 32 are provided on the same plane, but they may be provided so that their heights (distance from the wafer mounting surface 22a) are different from each other. For example, the height of the heater zone electrodes 31 and 32 may be adjusted to the height of the RF zone electrodes 24 and 25.

In the above-described embodiment, the RF electrode 23 is composed of the first and second RF zone electrodes 24 and 25 having different heights, but the RF electrode may be composed of three or more RF zone electrodes having different heights. FIG. 7 shows an example in which the RF electrode 23 is composed of the first to third RF zone electrodes 124 to 126 having different heights. In FIG. 7, the same components as those in the above-described embodiment are designated by the same reference numerals. In FIG. 7, for convenience, the connecting conductors, RF zone electrode conductors, and power supplies of the RF zone electrodes 124 to 126 are omitted, and the heater zone electrode conductors and power supplies of the heater zone electrodes 231 to 233 are also omitted. Further, each heater zone electrode 231 to 233 omits the wiring pattern and shows only the region where the coil is wired. These heater zone electrodes 231 to 233 are provided on the same plane. The first RF zone electrode 124 is a circular electrode concentric with the ceramic substrate 22, and the second and third RF zone electrodes 125 and 126 are annular electrodes concentric with the ceramic substrate 22. The first to third RF zone electrodes 124 to 126 are arranged in the order of the first RF zone electrode 124, the second RF zone electrode 125, and the third RF zone electrode 126 from the side closer to the wafer mounting surface 22a. The first to third heater zone electrodes 231 to 233 constituting the heater electrode 30 are provided so as to coincide with the first to third RF zone electrodes 124 to 126 when viewed in a plan view. Even with this configuration, the same effect as that of the above-described embodiment can be obtained. In particular, since different high-frequency power can be supplied to the first to third RF zone electrodes 124 to 126, the density distribution of the plasma can be better controlled. Further, since different electric power can be supplied to each of the first to third heater zone electrodes 231 to 233, the variation in film formation property for each zone can be compensated and adjusted by adjusting the heater temperature.

The heights h1 to h3 of the first to third RF zone electrodes 124 to 126 constituting the RF electrode 23 from the heater electrodes 30 can be arbitrarily set. For example, as shown in FIG. 7, the height of the first RF zone electrode 124 in the central portion from the heater electrode 30 may be the highest, and the height from the heater electrode 30 may decrease toward the outer circumference (h1>. h2> h3). Alternatively, on the contrary, the height of the first RF zone electrode 124 in the central portion from the heater electrode 30 may be the lowest, and the height from the heater electrode 30 may increase toward the outer circumference (h1 <. h2 <h3). Alternatively, the heights h1 to h3 of the RF zone electrodes 124 to 126 may be freely set, such as h1> h2 <h3 or h1 <h2> h3.

In the above-described embodiment, the RF electrode 23 is composed of the first RF zone electrode 24 of the circular electrode and the second RF zone electrode 25 of the annular electrode, but the second RF zone electrode 25 which is the annular electrode is divided into a plurality of parts. An AC power supply may be individually connected to each divided electrode, or the first RF zone electrode 24, which is a circular electrode, may be divided into a plurality of electrodes and an AC power source may be individually connected to each divided electrode. In this way, the density distribution of the plasma can be easily controlled to be better. FIG. 8 illustrates a case where the second RF zone electrode 25 constituting the RF electrode 23 is divided into three arcuate electrodes 251 to 253. The arcuate electrodes 251 to 253 may all have the same height, may have different heights, or may have two identical heights and one different height. FIG. 9 illustrates a case where the second RF zone electrode 25 constituting the RF electrode 23 is divided into three arcuate electrodes 251 to 253, and the first RF zone electrode 24 is further divided into two semicircular electrodes 241,242. .. The semicircular electrodes 241,242 may have the same height or different heights.

In the above-described embodiment, the ceramic substrate 22 has a flat surface, but the step-type ceramic substrate 422 shown in FIG. 10 may be adopted. In FIG. 10, the same components as those in the above-described embodiment are designated by the same reference numerals. The surface of the ceramic substrate 422 has an annular stepped surface 422a on the outer peripheral portion. The stepped surface 422a is one step lower than the wafer mounting surface 22a. In this ceramic substrate 422, the dielectric thickness from the inner first RF zone electrode (circular electrode) 24 to the wafer mounting surface 22a and the dielectric from the outer second RF zone electrode (annular electrode) 25 to the stepped surface 422a. It may be the same as the thickness. In this way, the plasma density inside and outside can be made uniform. Alternatively, the pocket-type ceramic substrate 522 shown in FIG. 11 may be adopted. In FIG. 11, the same components as those in the above-described embodiment are designated by the same reference numerals. The surface of the ceramic substrate 522 has an annular stepped surface 522a on the outer peripheral portion. The stepped surface 522a is one step higher than the wafer mounting surface 22a. The RF electrode 23 is composed of an inner first RF zone electrode (circular electrode) 24 and an outer second RF zone electrode (annular electrode) 525. The second RF zone electrode 525 is connected to the second AC power supply (see FIG. 2) via the connecting conductor 527, the electrode terminal 25a, and the second RF zone electrode conductor 35. Further, the second RF zone electrode 525 is arranged at a higher position than the first RF zone electrode 24. In the ceramic substrate 522, the dielectric thickness from the first RF zone electrode 24 to the wafer mounting surface 22a may be the same as the dielectric thickness from the outer second RF zone electrode 525 to the stepped surface 522a. In this way, the plasma density inside and outside can be made uniform.

Further, although the surface of the ceramic substrate 22 is flat in FIG. 7, the ceramic substrate 622 with an annular groove shown in FIG. 12 may be adopted. In FIG. 12, the same components as those in the above-described embodiment are designated by the same reference numerals. The surface of the ceramic substrate 622 has an annular groove 622a concentric with the ceramic substrate 622. The RF electrode 23 is composed of an inner first RF zone electrode (circular electrode) 624, an outer second RF zone electrode (annular electrode) 625, and an outer third RF zone electrode (annular electrode) 626. ing. The second RF zone electrode 625 is connected to the second AC power supply 45 (see FIG. 2) via the connecting conductor 627, the electrode terminal 25a, and the second RF zone electrode conductor 35. The third RF zone electrode 626 is connected to a third AC power supply (not shown) via a connecting conductor 628, an electrode terminal 626a, and a third RF zone electrode conductor 636. The dielectric thickness from the first RF zone electrode 24 to the wafer mounting surface 22a, the dielectric thickness from the second RF zone electrode 625 to the bottom surface of the annular groove 622a, and from the third RF zone electrode 626 to the wafer mounting surface 22a. It may be the same as the dielectric thickness. In this way, the plasma density inside and outside can be made uniform.

In the above-described embodiment and the embodiment shown in FIG. 7, the number of divisions of the RF electrode 23 and the number of divisions of the heater electrode 30 are the same, but the number of divisions of the two may be different.

In the above-described embodiment, the first and second RF zone electrodes 24 and 25 and the connecting conductor 27 are all made of a conductive mesh sheet, but the present invention is not particularly limited to the mesh sheet, and for example, the conductive mesh sheet is used. A uniform sheet (metal foil, etc.) may be used.

In the above-described embodiment, the wafer W may be attracted to the wafer mounting surface 22a by applying a voltage to the RF electrode 23. Further, the wafer W may be attracted to the wafer mounting surface 22a by further embedding an electrostatic electrode in the ceramic substrate 22 and applying a voltage to the electrostatic electrode.

In the above-described embodiment, an example of the manufacturing method of the wafer support base 20 is shown, but the manufacturing method of the wafer support base 20 is not particularly limited to this, and the wafer support base 20 can be manufactured by another known manufacturing method. It may be manufactured. For example, the wafer support base 20 may be manufactured according to the manufacturing method described in Japanese Patent Application Laid-Open No. 2012-89694.

This application is based on the priority claim of Japanese Patent Application No. 2018-127620 filed on July 4, 2018, all of which is incorporated herein by reference.

The present invention can be used when plasma processing a wafer.

10 Plasma generator, 20 wafer support, 21 yen, 22 ceramic substrate, 22a wafer mounting surface, 22b back surface, 22c central region, 23 RF electrode, 24, 124 1st RF zone electrode, 24a electrode terminal, 25, 125th 2RF zone electrode, 25a electrode terminal, 27 connecting conductor, 29 ceramic shaft, 30 heater electrode, 31,131,181,231 1st heater zone electrode, 31a, 31b electrode terminal, 32,132,182,232 2nd heater Zone electrode, 32a, 32b electrode terminal, 34 1st RF zone electrode conductor, 35 2nd RF zone electrode conductor, 36 1st heater zone electrode conductor, 37 2nd heater zone electrode conductor, 44 1st AC power supply, 45 2nd AC power supply, 47 1st heater power supply, 48 2nd heater power supply, 50 upper electrode, 126 3rd RF zone electrode, 183 gap heater zone electrode, 233 3rd heater zone electrode, 241,242 semi-circular electrode, 251 to 253 Arc-shaped electrode, 422,522,622 ceramic substrate, 422a, 522a stepped surface, 525 second RF zone electrode, 527 connection conductor, 622a annular groove, 624 to 626 first to third RF zone electrodes, 626a electrode terminal, 627 , 628 Conductor for connection, 636 Conductor for 3rd RF zone electrode.

Claims (8)

A wafer support base in which RF electrodes and heater electrodes are embedded inside a disk-shaped ceramic substrate having a wafer mounting surface.
The RF electrode is composed of a plurality of RF zone electrodes provided for each zone in which the wafer mounting surface is divided into a plurality of zones.
The plurality of RF zone electrodes are provided in at least two stages having different distances from the wafer mounting surface.
The heater electrode is composed of a plurality of heater zone electrodes provided for each zone in which the wafer mounting surface is divided into a plurality of zones in the same manner as or different from the RF zone electrode.
The plurality of RF zone electrodes are independently connected to the plurality of RF zone electrode conductors through electrode terminals provided on the back surface of the ceramic substrate.
The plurality of heater zone electrodes are independently connected to the plurality of conductors for heater zone electrodes through electrode terminals provided on the back surface of the ceramic substrate.
The thickness of the ceramic substrate on each RF zone electrode is the same.
Wafer support. The RF electrode includes, as the plurality of RF zone electrodes, a circular electrode concentric with the ceramic substrate or an electrode obtained by dividing the circular electrode into a plurality of parts, and further, the circular electrode or an electrode obtained by dividing the circular electrode into a plurality of parts. On the outside, one or more annular electrodes concentric with the ceramic substrate or an electrode obtained by dividing at least one of the annular electrodes into a plurality of electrodes is included.
The wafer support according to claim 1. When the ceramic substrate is viewed from the wafer mounting surface, at least one heater zone electrode is arranged in the gap between the RF zone electrodes.
The wafer support according to claim 1 or 2. The heater zone electrode arranged in the gap is a gap heater zone electrode having the same shape as the gap.
The wafer support according to claim 3. The ceramic substrate is arranged so that the shapes of the plurality of RF zone electrodes and the shapes of the plurality of heater zone electrodes match when viewed from the wafer mounting surface.
The wafer support according to claim 1 or 2. The plurality of RF zone electrodes include a circular electrode concentric with the ceramic substrate, and one or more annular electrodes concentric with the ceramic substrate outside the circular electrode.
The plurality of heater zone electrodes constituting the heater electrode are provided on the same plane.
The height of the plurality of RF zone electrodes from the heater electrode is higher as the RF zone electrode is closer to the center of the ceramic substrate.
The wafer support according to any one of claims 1 to 5. The plurality of RF zone electrodes include a circular electrode concentric with the ceramic substrate, and one or more annular electrodes concentric with the ceramic substrate outside the circular electrode.
The plurality of heater zone electrodes constituting the heater electrode are provided on the same plane.
The height of the plurality of RF zone electrodes from the heater electrode is lower as the RF zone electrode is closer to the center of the ceramic substrate.
The wafer support according to any one of claims 1 to 5. The wafer support according to any one of claims 1 to 7.
A hollow ceramic shaft joined to the central region of the surface of the ceramic substrate opposite to the wafer mounting surface.
The plurality of RF zone electrode conductors and the heater zone electrode conductors are arranged inside the ceramic shaft.
Wafer support.

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